Fire damper



G. F. HARTMAN, JR 3,3433% FIRE DAMPER Filed Aug. 19, 1965 ATTOPA/EV United States Patent 3,341,971 FIRE DAMPER George F. Hartman, Jr., Toledo, Ohio, assignor to The American Warming & Ventilating, Inc., Toledo, Ohio, a corporation of ()hio Filed Aug. 19, 1965, Ser. No. 480,903 6 Claims. (Cl. 49-7) ABSTRACT OF THE DISQILOSURE An improved fire damper is provided in which individual fire damper blades are guided for vertical movement in a frame. The blades are held at the top of the frame by a fusible link and the blades then cooperate with one another when the link melts and the blades drop down across the frame. The damper further includes a sealing arrangement at the bottom and sides of the frame to provide an efiective seal against fire. In one form, the blades have a unique flange arrangement with insulating means associated therewith. The fire damper is also provided with a latch arrangement for automatically latching the blades in the extended position.

This invention relates to a fire damper and more particularly to an improved fire damper of the type often employed in air ducts and the like.

A fire damper in accordance with the invention has many advantages over those heretofore known. The new damper is less expensive than those heretofore known and the blades, when not in use, can be held compactly and out of the way of the duct or other unit in which they are located. The damper also is extremely reliable and embodies no pivots or pivot joints whatsoever which are capable of becoming stiff and inoperable because of dirt, rust, corrosion, and other impediments.

Basically, the new damper includes a frame containing a plurality of parallel damper blades which are separately and independently slidably mounted and guided on a plurality of parallel guide rods. The damper blades are held entirely to one side of the duct when not in use by a support which includes a fusible link, with the blades then moving along the guide rods under the influence of gravity or a spring when the fusible link parts. The last blade is then held by suitable latch at the opposite side of the duct to completely block the duct and stop fire which may be advancing therealong.

It is, therefore, a principal object of the invention to provide a fire damper having the advantages outlined above.

Other objects and advantages of the invention will be apparent from the following detailed description of preferred embodiments thereof, reference being made to the accompanying drawings, in which:

FIG. 1 is a view in central, vertical cross section of a fire damper embodying the invention, with the blades in a retracted, out-of-the-way position;

FIG. 2 is a view similar to FIG. 1 of the fire damper with the blades in an extended, fire-blocking position;

FIG. 3 is a view in elevation of the fire damper with the blades in the position shown in FIG. 2;

FIG. 4 is an enlarged, fragmentary view in cross section of the blades in the position shown in FIG. 1;

FIG. 5 is a view in perspective of one of the blades according to the invention;

FIG. 6 is a fragmentary, detailed view of a gravity operated latch for holding the most advanced or last blade in the extended position;

FIG. 7 is a detailed view of a slightly modified gravity latch which can be used in place of the latch of FIG. 6; and

3,34 i i l Patented Sept. 1 9, 1 967 FIG. 8 is a somewhat schematic view of modified damper blades embodying the invention with some of the blades in a retracted position and some in an extended position.

Referring to the drawing, and more particularly to FIGS. 13, a fire damper embodying the invention is indicated at 10 and includes upper and lower frame members 12 and 14, and side frame members 16 and 18. The

frame members need not be of any particular design, such depending upon the size of the damper 10 and the nature of the installation. When the frame is employed in a duct, it can be entirely within the duct or the upper portion can extend beyond the normal duct passage so that the damper blades do not impede the passage at all. In this instance, the side frame members 16 and 18 have diagonal, L- shaped guide bars 20 and 22 with one leg of the bar aflixed to the side frame members and the other leg ex tending toward the opposite side frame member and serving as side seals at the ends of damper blades 24 when extended.

Each of the damper blades 24 includes a main vertical section 26 having upper or first flanges 28 and lower or second flanges 30 which are bent beyond positions perpendicular to the planes of the sections 26 and preferably to angles from thirty to forty-five degrees beyond the perpendicular. Central portions of the flanges 28 and 30 have guide holes 32 and 34 formed therein to receive guide rods 36. The guide rods 36 extend across the upper and lower frame members 12 and 14 in a plane parallel to the longitudinal extent of the duct and are uniformly spaced apart by a distance slightly more than the width of the flanges 28 or 30. The rods can be suitably aflixed to the upper and lower frame members, as by welding, or can first be affixed to separate strips (not shown) at their up per and lower ends which are then affixed t0 the frame members 12 and 14, as by spot welding.

A baffle or fixed blade 38 is affixed to a short flange 46 of the frame member 12 and has a fixed flange 42 similar to the second flanges 3t} of the blades 24. The fixed blade 38 serves to hide or protect the movable blades 24 when in their retracted positions and also, in effect, constitutes the first blade when the blades move to their extended positions.

A suitable chain 44 is aflixed to a short flange 46 of the frame member 12 and extends around the second flanges 30 of the blades 24 when in their retracted position, the other end of the chain being attached to the fixed flange 42 of the blade 38. A fusible link 48 is connected in the chain 44 and is caused to separate by fusing when subjected to elevated temperatures, thereby to cause the chain 44 to separate and release the movable blades 24. If the blades are mounted horizontally, as shown, they will then fall to the closed or extended position shown in FIG. 2 under the influence of gravity. If the blades are vertically mounted at one side of the duct, they can be pulled across the duct by a spring connecting the last blade and the frame member 14, as is known in the art. In either event, when the chain 44 is released, the blades move toward the frame member 14 with the first flange 28 of the first of the blades 24 then overlapping and nesting with the fixed flange 42 of the blade 38. The first flanges of the remaining blades 24 then catch and nest with the second flanges of the adjacent blades to form an effective stop for any flames advancing along the duct. The side bars 20 and 22 also serve as seals or deterrents for the flame by bridging the space between the ends of the blades 24 and the frame members 16 and 18. A flange bar 50 is attached to the frame member 14- adjacent the second flange of the last damper blade to improve the seal at this frame member.

To assure that the blades 24 will remain in their ex- J tended position when a fire occurs, in spite of any force applied to the blades, a suitable latch for the last of the blades 24 can be used. As shown in FIG. 6, the latch can be -in the form of a cylindrical rod 52 guided in slots 54 of plates 56 located near the ends of the last blade 24, for example. In such an instance, the second flange 30 of this blade can be slotted to clear the plates 56 and then to push the rod 52 up the slots and to one side of the path of the flange until it moves beyond the rod 52. The rod 52 can then move back by gravity or by a spring to the original position above the second flange to prevent the possibility of the blade moving away from the frame member 14.

A modified latch is shown in FIG. 7, this latch being in the form of a hook-shaped plate 58 pivoted at 60 to the guide rod 36 and swingable to one side when the first flange 28, in this instance, of the last blade, and the second flange 30 of the second-to-1ast blade, passes by. The invention, however, is not limited to any particular latch arrangement for the blades 24.

A modified fire damper 62 is shown in FIG. 8. The damper 62 includes a plurality of movable fire damper blades 64 which are like the blades 24 to the extent that they have vertical sections 66, first flanges 68, and second flanges 70. In addition, however, the blades 64 have intermediate flanges 72 extending in the same direction as the second flanges 70. With this arrangement, the blades, when extended, are connected by the first flanegs 68 engaging the intermediate flanges 72 of the adjacent blades with a pocket 74 formed between the blades by the lower half of the straight section 66, the intermediate flange 72, the second flange 741, and the upper half of the straight section of the adjacent damper blade. This provides an insulating wall across the duct which more effectively stops heat from a fire as well as the fire itself from moving along the duct.

If desired, the pocket 74 can contain suitable insulation 76 affixed to the blades to provide a greater insulating effect than the air alone. When the insulation 76 is used, the second flanges 70 of the blades 64 need not be employed, unless desired to help support the insulation.

By making the lower part of each of the blades 64 below the intermediate flanges 72 longer than the upper part, some overlap of the pockets 74 or the insulation 76 is obtained for greater insulating effectiveness.

Various modifications of the above-described embodiments of the invention will be apparent to those skilled in the art, and it is to be understood that such modifications can be made without departing from the scope of the invention, if they are within the spirit and the tenor of the accompanying claims.

I claim:

1. A fire damper comprising a frame including at least two spaced frame members, a plurality of fire damper blades having first longitudinal flanges extending in common directions from corresponding edges therefrom, an intermediate flange on each of said blades extending from an intermediate portion of said blade in a direction op posite the first flange, and insulating means aflixed to each of said blades adjacent said intermediate flange and on the side of said intermediate flange opposite the first flange, the intermediate flange of one blade engaging the first flange of an adjacent blade when the damper is closed and the blades are in an extended position.

2. A fire damper according to claim 1 wherein the width of said insulating means exceeds the distance between said intermediate flange and said first flange of each of said blades.

3. A fire damper comprising a frame including at least two spaced vertical side frame members, a top frame member, and a bottom frame member, a plurality of damper blades having first and second longitudinal flanges extending in opposite directions, intermediate flanges extending outwardly from intermediate portions of said blades in a direction parallel to one of said longitudinal flanges, said intermediate flange of one blade engaging said first flange of an adjacent blade when the damper is closed and said blades are in an extended position, a plurality of vertical guide means extending downwardly from said top frame member to guide said blades in parallel, vertical directions parallel to the plane of the frame whereby a first longitudinal flange of one frame member engages a second longitudinal flange of the adjacent damper blade thereabove when said blades are extended, with the blades being disposed in a stepped configuration, said guide means being disposed transversely to the plane of the frame, and said bottom frame member having an upwardly projecting flange extending substantially the length thereof and located adjacent the guide means for the lowermost damper blade, said flange extending upwardly above the lower edge of said lowermost blade when said blades are extended to provide a lower seal with said lowermost blade.

4. A fire damper according to claim 3 wherein said guide means constitutes a rod for each of said blades, and said damper being characterized further by side sealing flanges extending inwardly from said side frame members and cooperating with the ends of said blades to provide seals along the side frame members when said blades are extended.

5. A fire damper comprising a frame including at least two spaced frame members, a plurality of damper blades having first and second longitudinal flanges extending in opposite directions, and intermediate flanges extending outwardly from intermediate portions of said blades in a direction parallel to one of said longitudinal flanges, a

plurality of guide means supported by said frame members, said guide means being disposed in a plane transversely of said frame members, the intermediate flanges of said blades cooperating with the upper flanges of lower, adjacent blades when said blades are extended, whereby the blade portion between the first flange and intermediate fiange of one blade form a pocket with a portion between the intermediate flange and the second flange of an adjacent blade.

6. A fire damper according to claim 5 further characterized by insulating means carried by each of said blades between said intermediate flange and the corresponding longitudinal flange.

References Cited UNITED STATES PATENTS 866,170 9/ 1907 Watson 20 2 X 916,288 3/1909 Fish 160202 X 1,095,152 4/1914 Volp 160-232 1,234,873 7/1917 Clampitt 16O--l 1,788,651 1/ 1931 Alderson 160202 X 3,204,691 9/ 196-5 Rohrman 160-202 7 3,273,632 9/1966 McCabe 1601 DAVID J. VVILLIAMOWS-KY, Primary Examiner.

HARRISON R. MOSELEY, Examiner.

I. K. BELL, Assistant Examiner. 

1. A FIRE DAMPER COMPRISING A FRAME INCLUDING AT LEAST TWO SPACED FRAME MEMBERS, A PLURALITY OF FIRE DAMPER BLADES HAVING FIRST LONGITUDINAL FLANGES EXTENDING IN COMMON DIRECTIONS FROM CORRESPONDING EDGES THEREFROM, AN INTERMEDIATE FLANGE ON EACH OF SAID BLADES EXTENDING FROM AN INTERMEDIATE PORTION OF SAID BLADE IN A DIRECTION OPPOSITE THE FIRST FLANGE, AND INSULATING MEANS AFFIXED TO EACH OF SAID BLADES ADJACENT SAID INTERMEDIATE FLANGE AND ON THE SIDE OF SAID INTERMEDIATE FLANGE OPPOSITE THE FIRST FLANGE, THE INTERMEDIATE FLANGE OF ONE BLADE ENGAGING THE FIRST FLANGE OF AN ADJACENT BLADE WHEN THE DAMPER IS CLOSED AND THE BLADES ARE IN AN EXTENDED POSITION. 